From 5e64991296f081b2b30ce4d85171a21844c010ff Mon Sep 17 00:00:00 2001
From: Bram Matthys <syzop@vulnscan.org>
Date: Sun, 28 May 2023 11:07:10 +0200
Subject: [PATCH] Fix CHATHISTORY BETWEEN accidentally including a message too
 much Reported by progval in https://bugs.unrealircd.org/view.php?id=5952

---
 src/modules/history_backend_mem.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/modules/history_backend_mem.c b/src/modules/history_backend_mem.c
index 63067405f..e7210ef7a 100644
--- a/src/modules/history_backend_mem.c
+++ b/src/modules/history_backend_mem.c
@@ -1023,9 +1023,23 @@ static int hbm_return_between(HistoryResult *r, HistoryLogObject *h, HistoryFilt
 	direction = hbm_return_between_figure_out_direction(h, filter);
 
 	if (direction == 1)
+	{
 		return hbm_return_after(r, h, filter);
-	else if (direction == 0)
-		return hbm_return_before(r, h, filter);
+	} else
+	if (direction == 0)
+	{
+		/* Create a temporary filter, swapping directions */
+		char *x, *y;
+		HistoryFilter f;
+		memset(&f, 0, sizeof(f));
+		f.cmd = HFC_BEFORE;
+		f.limit = filter->limit;
+		f.timestamp_a = filter->timestamp_b;
+		f.timestamp_b = filter->timestamp_a;
+		f.msgid_a = filter->msgid_b;
+		f.msgid_b = filter->msgid_a;
+		return hbm_return_after(r, h, &f);
+	}
 	/* else direction is -1 which means not found / invalid */
 
 	return 0;